IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0164487
(2008-06-30)
|
등록번호 |
US-8188185
(2012-05-29)
|
발명자
/ 주소 |
- Wang, James H.
- Funk, Sara A.
|
출원인 / 주소 |
- Kimberly-Clark Worldwide, Inc.
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
6 인용 특허 :
92 |
초록
▼
A biodegradable packaging film is provided. The film is formed from a blend that contains a thermoplastic starch and polylactic acid. Starch is a relatively inexpensive natural polymer that is also renewable and biodegradable. Polylactic acid is likewise an inexpensive synthetic polymer that is biod
A biodegradable packaging film is provided. The film is formed from a blend that contains a thermoplastic starch and polylactic acid. Starch is a relatively inexpensive natural polymer that is also renewable and biodegradable. Polylactic acid is likewise an inexpensive synthetic polymer that is biodegradable and renewable, yet also capable of providing increased tensile strength to the film. Although providing a good combination of biodegradability/renewability and increased tensile strength, the polylactic acid is also relatively rigid and can result in films having a relatively high stiffness (e.g., high modulus of elasticity) and low ductility. While more ductile than polylactic acid, the thermoplastic starch is often difficult to melt process in film forming processes and very sensitive to moisture and water vapor, reducing its ability to be used as a stand alone packaging film. In an effort to counteract the effect of such polymers, an aliphatic-aromatic copolyester is also employed in the blend of the present invention. While such copolyesters are biodegradable, they also possess the melt properties and ductility that lend them well to the formation of films. Although the combination of these polymers may achieve a good balance between biodegradability/renewability, high tensile strength, and good ductility (e.g., high peak elongation), it is still often difficult to achieve a precise set of mechanical properties as desired for packaging films. In this regard, the blend also contains a filler. Due to its rigid nature, the amount of the filler may be readily adjusted to fine tune the blend to the desired degree of ductility (e.g., peak elongation) and stiffness (e.g., modulus of elasticity).
대표청구항
▼
1. A biodegradable packaging film, wherein the film includes a blend that comprises at least one thermoplastic starch in an amount of from about 10 wt. % to about 60 wt. % of the blend, at least one polylactic acid in an amount of from about 1 wt. % to about 30 wt. % of the blend, at least one aliph
1. A biodegradable packaging film, wherein the film includes a blend that comprises at least one thermoplastic starch in an amount of from about 10 wt. % to about 60 wt. % of the blend, at least one polylactic acid in an amount of from about 1 wt. % to about 30 wt. % of the blend, at least one aliphatic-aromatic copolyester in an amount of from about 20 wt. % to about 70 wt. % of the blend, and at least one filler in an amount of from about 1 wt. % to about 25 wt. % of the blend, wherein the ratio of the total weight percentage of the aliphatic-aromatic copolyester and thermoplastic starch to the total weight percentage of the polylactic acid and filler is from 4 to about 10; wherein the film exhibits a peak elongation of from about 50% to about 600% at a strain rate of about 127 millimeters per minute in the machine direction. 2. The biodegradable packaging film of claim 1, wherein the thermoplastic starch constitutes from about 20 wt. % to about 50 wt. % of the blend. 3. The biodegradable packaging film of claim 1, wherein the polylactic acid constitutes from about 5 wt. % to about 25 wt. % of the blend. 4. The biodegradable packaging film of claim 1, wherein the aliphatic-aromatic copolyester constitutes from about 30 wt. % to about 60 wt. % of the blend. 5. The biodegradable packaging film of claim 1, wherein the filler constitutes from about 8 wt. % to about 15 wt. % of the blend. 6. The biodegradable packaging film of claim 1, wherein the thermoplastic starch includes from about 40 wt. % to about 90 wt. % of at least one starch and from about 10 wt. % to about 45 wt % of at least one plasticizer. 7. The biodegradable packaging film of claim 6, wherein the starch includes a modified starch. 8. The biodegradable packaging film of claim 6, wherein the plasticizer includes a polyol. 9. The biodegradable packaging film of claim 1, wherein the thermoplastic starch has a melt flow index of from about 0.05 to about 50 grams per 10 minutes, determined at a load of 2160 grams and temperature of 190° C. in accordance with ASTM Test Method D1238-E. 10. The biodegradable packaging film of claim 1, wherein the aliphatic-aromatic copolyester is formed from an aromatic monomer that includes terephthalic acid or a derivative thereof, phthalic acid or a derivative thereof, isophthalic acid or a derivative thereof, or a combination of the foregoing. 11. The biodegradable packaging film of claim 1, wherein the aliphatic-aromatic copolyester is represented by the following general structure: wherein,m is an integer from 2 to 10;n is an integer from 0 to 18;p is an integer from 2 to 10;x is an integer greater than 1; andy is an integer greater than 1. 12. The biodegradable packaging film of claim 1, wherein the aliphatic-aromatic copolyester includes polybutylene adipate terephthalate. 13. The biodegradable packaging film of claim 1, wherein the aliphatic-aromatic copolyester has a glass transition temperature of about 0° C. or less. 14. The biodegradable packaging film of claim 1, wherein the polylactic acid contains monomer units derived from L-lactic acid, D-lactic acid, racemic lactic acid, or mixtures thereof. 15. The biodegradable packaging film of claim 1, wherein the polylactic acid has a glass transition temperature of from about 10° C. to about 80° C. 16. The biodegradable packaging film of claim 1, wherein the filler includes inorganic oxide particles. 17. The biodegradable packaging film of claim 16, wherein the particles include calcium carbonate particles. 18. The biodegradable packaging film of claim 1, wherein the filler includes particles having an average size of from about 0.5 to about 10 micrometers. 19. The biodegradable packaging film of claim 1, wherein the film has a thickness of about 100 micrometers or less. 20. The biodegradable packaging film of claim 1, wherein the film exhibits an ultimate tensile strength in the machine direction of from about 1 to about 50 Megapascals and a Young's modulus in the machine direction of from about 100 to about 800 Megapascals. 21. The biodegradable packaging film of claim 1, wherein the film exhibits a ultimate tensile strength of from about 5 to about 40 Megapascals in the machine direction and a Young's modulus of from about 150 to about 650 Megapascals in the machine direction. 22. The biodegradable packaging film of claim 1, wherein the film exhibits an ultimate tensile strength of from about 1 to about 50 Megapascals in the cross-machine direction and a Young's modulus of from about 50 to about 600 Megapascals in the cross-machine direction. 23. The biodegradable packaging film of claim 1, wherein the film exhibits an ultimate tensile strength of from about 5 to about 40 Megapascals in the cross-machine direction and a modulus of elasticity of from about 100 to about 450 Megapascals in the cross-machine direction. 24. The biodegradable packaging film of claim 1, wherein the film is multi-layered and contains at least one base layer and at least one skin layer. 25. The biodegradable packaging film of claim 24, wherein the base layer includes the blend. 26. The biodegradable packaging film of claim 1, wherein the film exhibits a peak elongation of from about from about 150% to about 550% at a strain rate of about 127 millimeters per minute in the machine direction. 27. The biodegradable packaging film of claim 1, wherein the film exhibits a peak elongation of from about from about 150% to about 550% at a strain rate of about 127 millimeters per minute in the cross-machine direction. 28. The biodegradable packaging film of claim 1, wherein the film exhibits a Young's modulus in the machine direction of from about from about 100 to about 195 Megapascals.
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